How to Teach the ERG

By Joshua Fowler

In the field of hazmat, there is no publication more ubiquitous than the Emergency Response Guidebook. It is taught at nearly every basic hazmat and firefighter hazmat class, is carried on most fire rigs and is the go-to source for first-arriving officers at a hazmat incident.

It has even been converted into an app.

The challenge is making sure first responders understand both the importance of the ERG and how to properly and quickly use it during an emergency. Here’s a look at how the ERG came to be, what it is and how to use it to help hazmat and firefighter instructors convey the ERG’s importance in the hazmat world.

Developed by the US Department of Transportation, the ERG’s first edition was released in 1973 and has been continuously updated since. Designed to be used by responders during the initial phase of a hazardous materials incident, the ERG provides necessary information to take protective actions without conducting detailed risk assessments. It quickly and accurately identifies dangerous goods and provides appropriate response procedures.

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The guidebook is also a tool to familiarize responders with DOT labeling requirements and other related topics. In 2008, the ERG was endorsed by the United Nations as a standard reference guide for hazardous materials incidents around the world.

The ERG is organized by four-digit numerical codes known as UN numbers, which correspond to various types of hazardous materials. The United Nations has been issuing numbers to identify hazardous materials for international transport since the late 1970s. The UN number system is also known as the UN Global Hazard Identification System or the Globally Harmonized System for Hazardous Communication.

The system was developed by an international group of experts in response to the increasing complexity and global nature of hazardous materials transportation. The UN numbers act as a universal language for identifying hazardous materials, eliminating potential miscommunications due to different languages or labeling conventions.

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UN numbers are composed of four digits and can be displayed in one of two ways. The first method is displayed as an orange box with a black border and black numbers. This method must always be accompanied with the appropriate placard. The second method is the UN number inside the appropriate placard (either of these methods are acceptable).

For example, UN 1090 (Acetone) looks like this.

As hazardous materials transportation has become more complex and global, so have UN numbers. In 2003, additional three-character packaging codes were added to include more detailed information about the materials being transported.

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The guidebook includes detailed information on the chemicals involved, including their physical description, chemical characteristics, fire behavior and potential health hazards associated with each one. Additionally, it provides recommended response actions for incidents involving these substances in both fixed facilities and transportation settings.

One of the most important aspects of the ERG is the colored bordered pages at the beginning. These pages provide critical information about how to respond in an emergency situation and serve as a starting point for determining what course of action should be taken. They include instructions on notifying authorities, identifying hazardous materials, obtaining assistance from specialized response teams and initial steps for containing the emergency.

  • White Pages (pages 1-27): instructions and use, emergency numbers, safety precautions, notifications, hazard classification system, table of markings, railcar identification, GHS, intermodal containers and pipeline transportation
  • Yellow Pages (pages 28-91): ID number index
  • Blue Pages (pages 92-155): alphabetical material index
  • Orange Pages (pages 156-285): response guides with the left page being safety and the right page being response
  • Green Pages (pages 286-353): initial isolation and protective action distances
  • White Pages (354-392): user’s guide, PPE, decontamination, fire and spill control, BLEVE, terrorism/IEDs, glossary, publication data, response centers (US and Canada) and 24-hour emergency response telephone numbers

Additionally, it is important to consult these bordered pages before taking any action at an emergency scene. Using this information as a starting point, responders can assess the situation and make informed decisions about how to proceed based on the specific circumstances.

When pulling up on a potential hazmat scene, responders should follow these seven steps.


Carefully read the product label and safety data sheet of the hazardous material you are dealing with as they provide important hazard information.


Refer to the ERG and use its color-coded sections to identify the appropriate response procedures for your situation.


Follow all instructions on how to protect yourself and others from exposure, including wearing personal protective equipment.


If necessary, take any actions recommended in the ERG such as isolating or neutralizing materials, evacuating an area or calling additional emergency services for assistance.


Be prepared to communicate vital details about your incident and hazardous material by using standard phrases from the ERG’s emergency response guide numbers.


After the incident has been contained, follow proper decontamination procedures for personnel and equipment exposed to the hazardous material.


Monitor the affected area and personnel to ensure that all necessary safety protocols have been followed and no further exposure or harm is possible.

Accurate identification is key for proper response to a hazmat incident. Without this knowledge, emergency personnel cannot accurately assess the potential risks associated with the substance and respond accordingly.

By using the ERG to determine the UN number of a material, emergency responders can quickly access relevant response information and take appropriate action while controlling an incident.

It falls to instructors and training officers to ensure all first responders are familiar with this invaluable resource and use it promptly and accurately when responding to incidents involving hazardous materials. The importance and application of the ERG is something responders must understand initially and retrain on periodically. 

About the authorJosh Fowler is a 23-year veteran of the fire service and is currently a district chief for a municipal department in southeast Texas. He is the founder and owner of Charge The Line Leadership and lead instructor at Triangle Rescue specializing in incident command, hazmat and leadership for oil and gas industries.